USA - In recent months there has been increased naval activity and tensions between countries jostling for control off their coastlines. This includes Iran buzzing a US ship with a helicopter, leading defense companies in Israel and the United Arab Emirates (UAE) agreeing to work on unmanned surface vessels, tensions in the Black Sea off the coast of Ukraine, and tensions between the US, China, the Philippines and other countries. The exercise with the Israelis and Gulf countries is linked to threats in the region, particularly from Iran. Tehran continues to harass US ships in the Persian Gulf. In July, an Iranian drone attacked a commercial tanker in the Gulf of Oman, killing two crew members. This all appears to point to a new global focus on the sea and competition for naval supremacy. Competition at sea could have major ramifications. A naval arms race between Britain and Germany helped lead to World War I. The shadows of war are now growing over a swathe of water from Europe to Asia. Major trade routes and supply chain woes could be affected by naval rivalries. This has happened in the Gulf of Oman, where commercial ships have been attacked. The next clash could happen in the Black Sea or off the coast of Taiwan.